Does Oklahoma have the power to ban its state courts from citing, or using, Sharia law as a basis of legal decisions? On Monday, the 10th U.S. Circuit Court of Appeals, in Denver, will hear opposing arguments on that thorny constitutional question.

The case dates back to November 2010, when an overwhelming 70 percent of voters in the Sooner State approved the “Save our State Amendment,” which was meant to prevent Islamic law from ever taking hold in Oklahoma.

While Oklahoma has only 30,000 Muslims, out of population of 3.7 million, Oklahoma State Rep. Rex Duncan, the prime mover behind the measure, said it was a necessary “pre-emptive strike."

“I see this in the future somewhere in America,” the chair of the Oklahoma State House Judiciary Committee told ABC News. “It’s not an imminent threat in Oklahoma yet, but it’s a storm on the horizon in other states.”

The Oklahoma chapter of the Council of American-Islamic Relations filed suited to set aside the voter-approved amendment. Muneer Awad, the chapter's executive director charged that the measure trampled upon the First Amendment, which proscribes both government “establishment of religion” and interference with the “free exercise” of religion.

Federal District Court Judge Vicki Miles-LaGrange, appointed to the bench by former President Bill Clinton, sided with Awad and CAIR. There was a “substantial likelihood,” she ruled, that the ban did, in fact, run afoul of the so-called establishment clause.

In a brief filed with the federal appellate court, they argued, “Just as Mr. Awad’s First Amendment Rights are fundamental, so too are the voting rights of the 695,000 Oklahomans who voted in favor” of the state ballot measure.

The outcome of the court battle over Oklahoma’s Sharia ban, which ultimately may be decided by the U.S. Supreme Court, almost certainly will have an impact on efforts underway to enact similar bans in at least 20 other states.

Awad understands that. If the 10th Circuit rules in his favor, he said, it will be a victory over the mostly conservative state lawmakers around the country who are trying to prevent Sharia law from taking hold in their states.

The plaintiff in the lawsuit against the state of Oklahoma says that proposed Sharia bans are motivated not by real threats to the rule of law in Oklahoma and other states, but for “political reasons” by state lawmakers like Duncan.

But Duncan and other proponents of state Sharia bans point to Western countries where Sharia law has gained a toehold. In Great Britain, for instance, five Sharia courts have been established to adjudicate certain disputes within the Muslim community. The British government has gone along.

Awad and other opponents of Sharia bans say that proponents are caricaturizing Sharia, which means “Path” in Arabic.

However, the Council on Foreign Relations states that, strict interpretations of Sharia, the legal code in the majority of Muslim countries, “are used to justify cruel punishments such as amputation and stoning as unequal treatment of women in inheritance, dress and independence.”